In wireless communication networks, wireless traffic is increasing at an exponential rate. Not only is the number of user equipment (UE) increasing, but for some UEs, the amount of traffic (e.g., number of bits) per unit of time (e.g., per second) to be communicated is increasing. In particular, applications that demand higher amounts of traffic per unit of time, such as video, high-definition images, and the like, are seeing a significant increase in traffic.
Carrier aggregation (CA) is a technology that allows the UE, like a mobile telephone, to use one or more carriers in a wireless communication system, so as to possibly enhance the amount of traffic per unit of time for the UE. A carrier, or carrier wave or carrier signal, is a waveform that is modulated with an input signal for the purpose of conveying information. The carrier signal has an associated bandwidth that is used to convey the information according to the modulation scheme. When a UE uses more than one carrier, the UE can use the total bandwidth of the plurality of carriers. With a larger bandwidth, therefore, a UE may conduct a higher total amount of traffic communicated per unit of time, compared to a UE using a smaller bandwidth, with similar context such as status of channels.
CA enables multiple carrier signals to be simultaneously communicated between the UE and a supporting base station, typically, the UE may be configured with a set of carriers by a base station, such as an enhanced NodeB (eNB). In some instances, the carriers may be from different frequency bands to add greater bandwidth to support high data rate communications and operations, such as streaming video or large data files
Another technology is to rely on carrier switching or selection (CS) to enable the UE to support more carriers than its own capability. Carrier switching/selection among all carriers available to the serving base station may allow the UE to access more carriers over time. In this approach, component carriers are selected based on several factors, such as load balancing. While the CS approach generally requires significantly less UE enhancement than the CA approach, one drawback to CS is the transition time involved in carrier switching and selection.